Suspension lifting magnet



April 15, 1969 B. A. PALM 3,439,304

SUSPENSION LIFTING MAGNET Filed Aug. 21, 1967 I Sheet of 2 FIGJ v v v v v v Q Q 9 Q 0 0...... 0.0.0.... I I

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BERNHARD A PALM ATTO EYS April 15, 1969 B. A. PALM ,3

SUSPENS ION LIFTING MAGNET ATTORNEYS BERNHARD A. PALM,

United States Patent Oihce 3,439,304 Patented Apr. 15, 1969 3,439,304 SUSPENSION LIFTING MAGNET Bernhard A. Palm, Los Angeles, Calif., assignor to Buck Manufacturing Company, Los Angeles, Calif., a corporation of Delaware Filed Aug. 21, 1967, Ser. No. 662,154 Int. Cl. H01f 7/20 US. Cl. 335-291 3 Claims ABSTRACT OF THE DISCLOSURE This invention relates to suspension lifting magnets in general. More particularly this invention relates to improvements in the fabrication of magnetic pole structures of electromagnets.

An object of this invention is to provide an improved electromagnet in which at least one of the poles is fabricated from a single plate of magnetic material which is cut into trapezoidal sections which are thereafter overlapped and joined by welding, bolting or the like.

Another object of this invention is to provide an improved suspension type electromagnet which is adapted to be suspended over a conveyor transporting magnetic and nonmagnetic material which are to be separated from each other, the electromagnet being provided with poles fabricated to distribute the magnetic field over the width of the conveyor.

Still another object of this invention is to provide an electromagnet in which at least one of the poles is assembled of overlapping plates, the assembly having a narrow top surface joined to the top plate of the electromagnet and the bottom surface being substantially wider, the central pole of the electromagnet being provided with a distributor plate attached thereto, and the distributor plate having a width corresponding approximately to the width of the pole face formed by the overlapping plates.

Other and further objects of this invention will be apparent to those skilled in the art to which it relates from the following specification, claims and drawing in which, briefly:

FIG. 1 is a vertical sectional view of an electromagnet constructed in accordance with this invention and shown positioned over conveyors with which it is adapted to be employed;

FIG. 2 is an end view of the electromagnet with the housing thereof partially broken away to show the overlapping plate structure forming one of the poles thereof;

FIG. 3 is a plan view of a metal plate which is adapted to be cut into three trapezoidal sections along the broken lines shown thereon to form the overlapping pole structure; and

FIG. 4 is a plan view of one of the poles made of three overlapping trapezoidal sections cut as shown in FIG. 3.

Referring to the drawing in detail, reference numeral designates a container in which the electromagnet is positioned surrounded by cooling fluid such as oil. A terminal box 10a is attached to the side of the container and this box is provided with a cover 10b which is attached thereto by bolts 100. Two terminals such as terminal 11 are positioned in the box 10a and these terminals extend into the interior of the housing or container 10 to supply electric current to the magnet winding 12 to which these terminals are connected. The electromagnet is provided with a magnetic circuit including the end poles 13 of the same magnetic polarity, top plate 14 which extends between poles 13, and center pole 15. All of these members are made of magnetic material and they are attached together as by welding, suitable bolts or the like to form the magnetic circuit of the electromagnet. The top plate 14 is of substantially rectangular shape and the end parts thereof overlap the upper parts of the end poles 13.

Each of the end poles 13 is fabricated from a single plate such as shown in FIG. 3 which is out along lines 13d and 13e so that the plate is divided into three trapezoidal plates 13a, 13b and 13c. The central section 13a is of substantially isosceles trapezoidal shape. The square sides of plates 13b and are then abutted or joined and the adjacent parts of these plates are overlapped by the plate 134; with the longer top dimension of plate 13a being coextensive with the top shorter lengths of the plates 13b and 130, as shown in FIG. 4. This composite plate structure is such that the cross-sectional areas thereof taken along the lines A, B and C are substantially equal, although the width of the pole is substantially reduced from the Width of the single plate from which it is fabricated. The top width of each of the poles 13 is substantially equal to the width of the top plate 14, as shown in FIG. 2, and the width of the bottom corresponds substantially to the width of the conveyor 21. The two parts 13b and 13c which extend outerward from the central section at the bottom of each end pole are positioned on the inside of the pole structure facing the coil 12. This fabrication of the pickup pole 13 results in economical use of the material going into the construction thereof and at the same time makes it possible to build pickup magnets with wide pole faces to spread the magnetic field produced by the magnet over the width of the conveyor.

The center pole 15 is substantially round, and the electric coil or winding is provided thereto in two concentric sections 12 which are spaced slightly from eachother. The inner coil section is slightly spaced from the central core 15. Thus, the cooling oil provided inside of the container or housing 10 may circulate between these coil sections and between the inner section and the core. Radial members 19 are provided to the coil assembly, and these are assembled with the coil sections in a conventional manner.

The operation of this invention is as follows: The electromagnet structure is suspended above the end of a conveyor 20 or like mechanism on which material, including tramp magnetic material, is passed so that the tramp magnetic material is attracted and pulled into the concentrated magnetic field between the forward pickup pole 13 and distributor plate 16 and thus hugs the bottom surface of the conveyor 21 which moves in the direction of the distributor plate 16. It will be noted that the pickup pole 13 is provided with wings extending therefrom so that this pickup pole has a width equal to the width of the inside of housing 10 and also equal to the width of the conveyor. Also, the distributor pole 16, which is mounted on the pole face of the center pole 15, is approximately three times as wide as the center pole 15 and it is almost as Wide as the forward pickup pole 13 to provide a wide area of strong magnetic field for picking up the tramp magnetic material. As the tramp material is moved by the conveyor 21 toward the distributor pole 16, it has a tendency to roll and tumble on the under side of conveyor 21 so that any nonmagnetic material clinging thereto may shake loose therefrom. This nonmagnetic material drops down and is deposited at the end of conveyor 20 together with other nonmagnetic material carried by the conveyor. The magnetic material clings to the underside of conveyor 21 and is moved into the weaker magnetic field beyond the rear pole 13 where it is released and deposited into a suitable receptacle on the right hand side of divider wall 22, or onto another conveyor.

While I have shown a preferred embodiment of the invention, it will be understood that the invention is capable of variation and modification so that the form shown should be limited only by the scope of the claims appended hereto. 7

What I claim is:

1. In an electromagnet for lifting magnetic articles or for attracting tramp magnetic material from a conveyor or the like, the combination comprising a coil having connections through which an electric current is supplied thereto, a core of magnetic material having a pole positioned in said coil, said core having a top plate which is attached to said pole, said core also having an outer pole comprising a composite plate structure formed of an elongated plate which is cut into three substantially equal sections by making two cuts across said plate, said cuts being at an acute angle to each other, the outer ones of said sections abutting each other and overlapping the other of said sections so that each of said outer sections overlaps approximately one-half of said other section and the cross-sectional areas of the composite plate structure at different latitudes thereof are approximately the same, said composite plate structure having a top corresponding substantially to the width of said top plate to which said top is joined, said composite plate structure also having a bottom width approximating the diameter of said coil.

2. In an electromagnet for lifting magnetic articles or for attracting tramp magnetic material from a conveyor or the like, the combination as set forth in claim 1 further characterized in that said elongated plate is substantially rectangular and said cuts are made so that said sections are trapezoidal.

3. In an electromagnet for lifting magnetic articles or for attracting tramp magnetic material from a conveyor or the like, the combination as set forth in claim 2 further characterized in that said elongated plate is substantially rectangular and said other section is of an isosceles trapezoidal shape.

Referencs Cited UNITED STATES PATENTS 1,190,647 7/1916 Hedenskoog 335-291 1,608,677 11/1926 Sederholm 335--289 GEORGE HARRIS, Primary Examiner.

US. Cl. X.R. 

